Many conventional target-tracking systems use a Kalman filter to track targets. During tracking, a target may occasionally be hidden in a Doppler-blind zone. A Doppler-blind zone is a region where there is little or no Doppler discriminant between the target and clutter returns. When a target moves into a Doppler-blind zone, clutter may mask any useful measurements.
One difficulty with these conventional target-tracking systems for targets that are occasionally hidden in a Doppler-blind zone is that track continuity is difficult to maintain. For example, when a target moves into a Doppler-blind zone, the target may remain there long enough for a tracker to lose it. Furthermore, sufficient time may elapse while the target is in the Doppler-blind zone that it may be impossible to reacquire and/or intercept the target when it does emerges from the blind zone. The loss of the target and/or the reacquisition delay can become a significant danger in some situations, especially when the target enters a blind zone repeatedly or at a critical time.
Thus, there are general needs for improved systems and methods that track targets. There are also needs for tracking systems and methods that help maintain track continuity of beam-aspect targets. There are also needs for tracking systems and methods that more quickly reacquire beam-aspect targets emerging from a blind zone.